Driving hammer



Sept. 11, 1962 w. R. FAIRCHILD 3,053,231

DRIVING HAMMER Filed Feb. 8, 1960 2 Sheets-Sheet 1 m w w M 7/? a f Mm INVENTOR WILLIAM R. FAlRCHlLD ATTORNEY FEB.

Sfeptt 111,, 1962; R. FAl-RCHLLD 3,053,231

DRIVING. HAMMER Filed Kent 85; 19603 2 Sheets-Sheet 2 v INVENTOR WILLIAM R FAiRCHlLD F \cs 5 ATTORNEY United States Patent 3,053,231 DRIVING HAMMER William R. Fairchild, P.0. Box 31, Hattiesburg, Miss.

Filed Feb. 8, 1960, Ser. No. 7,357 l Claims. (Cl. 121-30) This invention relates to an improved pneumatic hammer, especially steam hammers, for driving pile.

Steam hammers are important for driving pile into the earth in order to obtain suitable foundation or support in building bridges, roads and the like. Such hammers are generally positioned between guide bars or hammer leads which are mounted in'a suitable frame positioned above the pile tofl be driven. When'the pile is to be driven, the hammer is lowered so that the weight ofthe steam hammer rests on the pile. As the ram in the steam hammer is operated, the force of the'blows of the ram striking the top of the pile forces the pile into the earth.

As a general rule, such steam hammers are large and heavy. An average steam hammer which has a piston stroke of 3 feet-is about 12'feet in'height and weighs about 11,000 pounds. In such a hammer, the ram or the striking part of the machine weighs about 5,000 pounds, and with a three foot stroke of the ram, a force of 15,000 foot pounds of striking force is imparted to the top of the pile.

With so much weight of the steam hammer and powerful striking force of the ram within the steam hammer involved, the machine is subjected to tremendous shock and vibration, and the useful life of the parts of the steam hammer is relatively short.

It is therefore an object of the present invention to provide a steam hammer in which the useful life of the parts of the hammer is increased.

Another object is to provide a steam hammer in which the parts which are subjected to severe shock and vibration are cushioned and thereby prevent frequent breakdown of the machine.

Another object is to arrange a multiplicity of cushioning elements in the ram elements which are so compressed to permit a cushioning effect for the ram elements and, at the same time, take up slack resulting from wear of the parts in the unit.

Other objects and benefits of my invention will be apparent to those skilled in the art from the following description and claims with reference to my improved steam hammer.

FIGURE 1 is a front view of a steam hammer partly in section,

FIGURE 2 is a side elevation in section on line 2-2 of a steam hammer showing arrangement of spring elements recessed in the ram recess,

FIGURE 3 is a section through the steam hammer on line '3-3 showing spacing of the springs in the upper portion of the ram,

FIGURE 4 is an enlarged view on line 44 of FIG. 3 to more clearly show the arrangement of the spring elements, and

FIGURE 5 is an enlarged view showing the spring element mounted at the base of the slide bar of the hammer.

In my copending application Serial No. 699,788, filed November 29, 1957, now issued as Patent 2,975,761, dated March 21, 1961, reference is made to the spring element at the base of the slide :bar of the hammer and the benefit derived in using the spring. This application is a continuation-in-part of my copending application Serial No. 699,788 referred to above.

Referring to the drawing, the steam hammer comprises ram which is positioned at the end of piston rod 12. At the opposite end of piston rod 12, a piston 14 is mounted which moves within cylinder 16 as steam enters the 3,053,231 Patented Sept. 11, 1962 cylinder from steam chest 18. Entry of steam from chest 18 is controlled by rotary valve 20.

Ram 10 is slidably mounted on four columns 22, the columns passing through the body of the ram and being spaced from each other, that is, the four columns are positioned adjacent to the corners of ram 10 as shown in FIGURE 3. The columns 22 extend from base 24 of the structure through the body of ram 10, through the base 26 of the cylinder as shown in FIGURES 1 and 2. A cylinder cap or boss 28 is at the top of cylinder 16. Suitable compression springs 30 are mounted on the columns 22 as described and claimed in my copending application.

In the ram recess 32, a plurality of springs 34 are uniformly spaced or positioned around piston rod 12. It is desirable to have at least three springs, but more eflicient operation may be obtained if the number of springs is greater. It is preferred that four or six springs be used and positioned around the shaft as shown in FIGURE 3. The springs 34 are positioned between spring plates 36 and 38 and anchored to the ram 10 by means of securing means as bolts 40, which pass through spring plates 36 and 38, and through springs 34. The compression on the springs may be varied by adjusting the nuts 42 on bolts 40.

The positive pressure exerted by the springs 34 on the plate 3 8 also imparts a pressure on the piston rod bushing 42. It is preferable to have a cushion plate 44 and a lead cushion 46 between the end of piston rod 12 and the ram point 48.

A spring 50 under compression is also used at the end of slide bar 52. The slide bar 52 passes through spring 50 and contacts the lower spring plate 54, which in turn pressed against the slide bar bushing 56 as shown in FIG- URE 5. A steel cushion plate 58 and a lead cushion 60 are used similarly as is done in connection with the springs surrounding piston rod 12. The upper spring plate 62 anchored to the ram 10 by means of stud bolts 64 and nuts 66 holds the spring assembly at the end of slide bar 52 in place.

As shown in the drawings, the slide bar 52 is connected in the upper portion of the ram 10 and held securely in place by means of spring 50 and spring plate 62. When the hammer is in operation and ram 10 is raised, slide bar 52 is raised with the ram. The earns 53 mounted on slide bar 52 actuate rotary valve 20 controlling entry of steam into the steam cylinder, to cause upward movement of the steam piston, which then raises ram 10. Through this arrangement of spring mountings in the ram recess receiving the piston rod 12, and in the ram recess receiving the slide bar 52, severe shock and vibration of the parts is substantialy reduced.

The spring assemblies spaced around piston rod 12 and also the spring 50 at the end of the slide bar together form a resilient cushion for the hammer and, at the same time, the relatively high compression under which the springs are held takes up any slack due to wearing action on the parts. These springs hold the piston rod and the piston bushing firmly in contact with the cushion plate so there is no slack and, at the same time, have sufiicient play or give, as it is sometimes called, to prevent fracture. Similarly, the slide bar is held firmly in the same manner which prevents slack. Through this, the parts are held or locked firmly and securely at all times during operation. Since no slack will develop between the parts, the usable life thereof will be extended. The shock and vibration will be greatly reduced while using the hammer, and through such mountings the destructive shock on the apparatus is absorbed.

Various changes may be made in this embodiment of my invention as will be apparent to those skilled in the art but such changes are intended to be within the scope of the appended claims.

I claim:

1. A steam hammer comprising a cylinder, a reciprocating piston within said cylinder, a piston rod having one end fixed to the piston extending through the cylinder base and resiliently anchored to a movable ram, a recess in said ram, a plurality of spring means anchored to the lower portion of the ram recess, said springs being held in place under compression and uniformly spaced around the piston rod.

2. A steam hammer as defined in claim 1, and wherein a pair of spaced plates hold the springs under compression in fixed position.

3. A steam hammer comprising a cylinder, a reciprocating piston within said cylinder, a piston rod having one end fixed to the piston extending through the cylinder base and resiliently anchored to a movable ram, a recess in said ram, a pair of spaced plates positioned in the recess, coiled springs positioned between the plates, said springs being held under compression and uniformly spaced around the bottom of the recess, and in uniform spaced relation with the piston rod.

4. A steam hammer comprising a cylinder, a reciprocating piston within said cylinder, a piston rod having one end fixed to the piston extending through the cylinder base and resiliently anchored to a movable ram, a recess in said ram, a plurality of uniformly spaced springs under compression positioned around and in spaced relation to the piston rod between the walls of the recess and the piston rod, a movable slide bar connected to said movable ram for actuating a steam valve to admit steam to the cylinder, a spring under compression surrounding the end of the slide bar, and means to hold said slide bar spring in position.

5. A steam hammer as defined in claim 4, and wherein fixed spaced plates hold the compressed and spaced springs surrounding the piston rod and the spring at the base of the slide bar in place.

References Cited in the file of this patent UNITED STATES PATENTS 284,282 Cram Sept. 4, 1883 659,712 Stiles Oct. 16, 1900 1,307,590 Mackie June 14, 1919 1,525,623 Stone Feb. 10, 1925 1,740,818 Killingsworth Dec. 24, 1929 2,798,363 Hazak et a1. July 9, 1957 FOREIGN PATENTS 681,270 France May 13, 1930 

